An invention relating to a method of manufacturing ceramic ware having numerous wrinkles on its surface is described in Japanese Patent Application Publication No. 2000-263521. This manufacturing method is one in which clay is placed on the surface of an inflated rubber balloon, and then, by deflating the rubber balloon, numerous wrinkles are formed on the surface of the clay, and thereafter the clay is baked. Also, in the first column of the specification of Japanese Patent Application Publication No. 2000-263521, in lines 16 to 17 there is a description to the effect that it is also possible to form the wrinkles on the clay by means of a flat board shaped elastic plate.
While in Japanese Patent Application Publication No. 2000-263521 there is no disclosure regarding application of a flat board shaped sheet material in clay (ceramic sheet) having numerous wrinkles on the surface thereof, the sheet material could be considered to be used for example to cover a revetment of a river or the walls and the like of various kinds of buildings. In the case where, for example, it is used to cover a revetment of a river, by nurturing micro organisms inside the wrinkles and breaking down pollutants by these micro organisms, it becomes possible to clean up the river. Also, since a ceramic sheet having numerous wrinkles has superior sound absorption properties compared to a simple flat board shaped ceramic sheet, in the case where such a ceramic sheet is used for a wall panel to cover the wall surface of a room such as a hall, excellent acoustic properties can be achieved while maintaining a profound and dignified design for the interior walls of the room.
In Japanese Patent Application Publication No. 2000-263521 there is no disclosure of a specific apparatus for forming wrinkles in clay by means of a flat board shaped elastic plate. Moreover, for the manufacturing method, only basic elements are disclosed. Therefore it may be considered that in cases it may be difficult to efficiently obtain good quality ceramic sheets with the invention as it stands. This point is explained, with reference to FIG. 6.
In the case where the product is used to cover a revetment of a river, in order to have the river water enter into the inner part of the wrinkles so that the breakdown of pollutants can be efficiently carried out, as shown in FIG. 6(A), it is necessary that concave parts 1 of the wrinkles be of such a shape as to open surely at the surface of a ceramic sheet 2. As shown in FIG. 6(B), in the case where the tips of convex parts 3 that constitute the wrinkles contact each other, and the concave part 1 that constitutes the wrinkle is not open, water becomes unable to enter into the inner part of the concave part 1. As a result the inner part of the concave parts 1 do not contribute to the nurturing of micro organisms and the breakdown of pollutants. Also, in the case where the ceramic sheet 2 is used as a wall panel of a room, if the concave parts 1 do not open at the surface of the ceramic sheet 2 as shown in FIG. 6(B), then sound absorption by the concave parts 1 is not effectively carried out, and it becomes difficult to make the acoustic properties of the room such as a hall follow the design.
In consideration of these issues, in order to exhibit the expected performance in a corrugated sheet material such as the above mentioned ceramic sheet 2, it is desirable to realize a manufacturing method for a corrugated sheet material in which the tips of the convex parts 3 that constitute the wrinkles do not contact with each other, and the concave parts 1 open surely at the surface, and a device that is capable of implementing this manufacturing method.